Abstract: A one piece, fiber reinforced, plastic radiator cooling fan for a truck. The fan is reinforced by: a hub extension which extends from the hub into each blade a substantial distance; by directly interconnecting the leading and trailing edges of adjacent blades to form a juncture therebetween in the form of a spiral located radially outwardly from the hub; by having the leading and trailing edges of adjacent hub extensions interconnect in a smoothly curved line tangent to the hub; by strengthening locations of high stress in each blade; and by avoiding sudden changes in thickness and in direction of the various portions of the fan.